Ventricular remodeling after myocardial infarction. Experimental observations and clinical implications

microRNA-17-5p downregulation inhibits autophagy and myocardial remodelling after myocardial infarction by targeting STAT3

MicroRNAs (miRs) are reported to regulate myocardial infarction (MI). This study was performed to investigate the function and mechanism of miR-17-5p in myocardial remodelling after MI. Initially, a mouse model of MI was established and MI mice were infected with lentivirus antago-miR-17-5p vector. High expression of miR-17-5p was found in myocardial tissues after MI. After inhibiting miR-17-5p expression, myocardial fibrosis, scarring, and cardiomyocyte apoptosis were improved, LC3-II/LC3-I ratio and Beclin-1 expression were decreased but p62 expression was increased. The dual-luciferase assay suggested that miR-17-5p targeted STAT3 and negatively regulated its expression. Then, after inhibiting STAT3 expression using STAT3 inhibitor S31-201, the fibrosis, scarring, and cardiomyocyte apoptosis were deteriorated, along with the rise of LC3-II/LC3-I and Beclin-1 expression, the reduction of p62 expression and the reversion of MI attenuation. In conclusion, inhibition of miR-17-5p can inhibit myocardial autophagy through targeting STAT3 and then inhibit myocardial remodelling, thereby protecting the myocardium after MI.

Injectable AuNP-HA matrix with localized stiffness enhances the formation of gap junction in engrafted human induced pluripotent stem cell-derived cardiomyocytes and promotes cardiac repair

Cell therapy offers a promising paradigm for heart tissue regeneration. Human induced pluripotent stem cells (hiPS) and their cardiac derivatives are emerging as a novel treatment for post-myocardial infarction repair. However, the immature phenotype and function of hiPS-derived cardiomyocytes (hiPS-CMs), particularly poor electrical coupling, limit their potential as a therapy. Herein, we developed a hybrid gold nanoparticle (AuNP)-hyaluronic acid (HA) hydrogel matrix encapsulating hiPS-CMs to overcome this limitation. Methacrylate-modified-HA was used as the backbone and crosslinked with a matrix metalloproteinase-2 (MMP-2) degradable peptide to obtain a MMP-2-responsive hydrogel; RGD peptide was introduced as an adhesion point to enhance biocompatibility; AuNPs were incorporated to regulate the mechanical and topological properties of the matrix by significantly increasing its stiffness and surface roughness, thereby accelerating gap junction formation in hiPS-CMs and orchestrating calcium handling via the α_nβ1integrin-mediated ILK-1/p-AKT/GATA4 pathway. Transplanted AuNP-HA-hydrogel-encapsulated-hiPS-CMs developed more robust gap junctions in the infarcted mice heart and resynchronized electrical conduction of the ventricle post-myocardial infarction. The hiPS-CMs delivered by the hydrogels exerted stronger angiogenic effects, which also contributed to the recovery process. This study provides insight into constructing an injectable biomimetic for structural and functional renovation of the injured heart.

The brief methylprednisolone administration is crucial to mitigate cardiac dysfunction after myocardial infarction

Acute myocardial infarction (AMI) is one of the major causes of heart failure and mortality. Glucocorticoids administration post-infarction has long been proposed, but it has shown conflicting results so far. This controversy may be associated with the glucocorticoid type and the period when it is administered. To elucidate these, the present aims to evaluate if the brief methylprednisolone acetate administration is determinant for heart adaptation after AMI. Male Wistar rats were divided into 3 groups: sham-operated (SHAM); infarcted (AMI); infarcted treated with methylprednisolone acetate (AMI+M). Immediately after surgery, the AMI+M group received a single dose of methylprednisolone acetate (40 mg/kg i.m.). After 56 days, the cardiac function was assessed and lungs, liver and heart were collected to determine rates of hypertrophy and congestion. Heart was used for oxidative stress and metalloproteinase activity analyses. Methylprednisolone acetate attenuated matrix metalloproteinase-2 activity, cardiac dilatation, and prevented the onset of pulmonary congestion, as well as avoided cardiac hypertrophy. Our data indicate that administration of methylprednisolone acetate shortly after AMI may be a therapeutic alternative for attenuation of detrimental ventricular remodeling.

Acute Kidney Injury Increase Risk of Left Ventricular Remodeling: A Cohort of 1,573 Patients

Background: Acute kidney injury (AKI) is a common complication after coronary angiography (CAG) and associated with heart failure (HF). Left ventricular (LV) remodeling is a vital process in the progression of HF. However, few studies investigate the relationship between AKI and LV remodeling.

Methods: We included consecutive patients undergoing CAG from January 2007 to December 2018 at Guangdong Provincial People’s Hospital (NCT04407936). AKI was defined as an absolute increase in serum creatinine (Scr) of ≥ 0.3mg/dl or a ≥ 50% increase in Scr from baseline within the first 48–72 h after the procedure. LV remodeling was defined as: (1) an absolute decrease in left ventricular ejection fraction (LVEF) of ≥ 10% compared to baseline, or (2) a follow-up LVEF < 40%. Univariate and multivariate logistical regressions were used to assess the association between AKI and LV remodeling.

Results: Of the 1,573 patients (62.2 ± 9.7 years, female 36.7%) included in the study, 231 (14.7%) had AKI. The incidence of LV remodeling was higher in patients with AKI than in those without AKI (24.7% vs. 14.5%). After adjusting for confounding, multivariate logistic regression showed that AKI was associated with a significantly higher risk of LV remodeling [adjusted odds ratio (aOR) 1.87; 95% CI, 1.30–2.66; p < 0.001]. In addition, LV remodeling patients had higher all-cause mortality compared to non-LV remodeling patients (9.7% vs. 19.1%).

Conclusion: Our data suggested that AKI is present in up to 15% of patients after CAG and that nearly a quarter of AKI patients suffered LV remodeling and AKI patients have a two-fold risk of developing LV remodeling than non-AKI patients. Our findings suggest that more active measures be taken not only to prevent AKI patient developing into LV remodeling, but to prevent patients undergoing CAG from developing AKI.

Clinical Assessment of Ventricular Wall Stress in Understanding Compensatory Hypertrophic Response and Maladaptive Ventricular Remodeling

Ventricular wall stress (WS) is an important hemodynamic parameter to represent myocardial oxygen demand and ventricular workload. The normalization of WS is regarded as a physiological feedback signal that regulates the rate and extent of ventricular hypertrophy to maintain myocardial homeostasis. Although hypertrophy is an adaptive response to increased biomechanical stress, persistent hypertrophic stimulation forces the stressed myocardium into a progressive maladaptive process called ventricular remodeling, consisting of ventricular dilatation and dysfunction in conjunction with the development of myocyte hypertrophy, apoptosis, and fibrosis. The critical determinant of this pathological transition is not fully understood, but an energetic mismatch due to uncontrolled WS is thought to be a central mechanism. Despite extensive basic investigations conducted to understand the complex signaling pathways involved in this maladaptive process, clinical diagnostic studies that translate these molecular and cellular changes are relatively limited. Echocardiographic assessment with or without direct measurement of left ventricular pressure used to be a mainstay in estimating ventricular WS in clinical medicine, but in recent years more and more noninvasive applications with magnetic resonance imaging have been studied. In this review article, basic clinical applications of WS assessment are discussed to help understand the progression of ventricular remodeling.

VEGF121 Mediates Post-Hypoxia Cardioprotective Effects Via CaSR and Mitochondria-Dependent Protease Pathway

BACKGROUND

Cardiovascular disease is the major cause of death worldwide. Hypoxia-mediated apoptosis in cardiomyocytes is a major cause of cardiovascular disorders. Treatment with vascular endothelial growth factor (VEGF) protein has been tested but operational difficulties have limited its use. However, with the advancements of gene therapy, interest has risen in VEGF-based gene therapy in cardiovascular disorders. However, the precise mechanism by which VEGF replenishment rescues post-hypoxia damage in cardiomyocytes is not known.

OBJECTIVES

To investigate the effect of post-hypoxia VEGF121 expression using neonatal rat cardiomyocytes.

METHODS

Cardiomyocytes isolated from neonatal rats were used to establish an in vitro model of hypoxia-induced cardiac injury. The effect of VEGF overexpression, alone or in combination with small-molecule inhibitors targeting calcium channel, calcium sensitive receptors (CaSR), and calpain on cell growth and proliferation on hypoxia-induced cardiomyocyte injury were determined using an MTT assay, TUNEL staining, Annexin V/PI staining, lactate dehydrogenase and caspase activity. For statistical analysis, a value of P<0.05 was considered to be significant.

RESULTS

The effect of VEGF121 was found to be mediated by CaSR and calpain but was not dependent on calcium channels.

CONCLUSIONS

Our findings, even though using an in vitro setting, lay the foundation for future validation and pre-clinical testing of VEGF-based gene therapy in cardiovascular diseases.

Left ventricular dimensions and cardiovascular outcomes in systolic heart failure: the WARCEF trial

Aims

There is limited information on the association between left ventricular (LV) dimensions and cardiovascular (CV) outcomes in patients with heart failure (HF) with reduced LV ejection fraction (HFrEF) receiving recommended HF treatment. We investigated the association between LV dimensions and CV outcomes in HFrEF patients receiving recommended HF treatment.

Methods and results

We investigated the association between LV echocardiographic dimensions and CV outcomes using conventional Cox models in 1138 HFrEF patients in sinus rhythm randomized to warfarin or aspirin treatment in the Warfarin vs. Aspirin in Reduced Cardiac Ejection Fraction (WARCEF) trial. LV enlargement, whether by diameter [LV end‐diastolic diameter index (LVEDDI) and LV end‐systolic diameter index (LVESDI)] or volume [LV end‐diastolic volume index (LVEDVI) and LV end‐systolic volume index (LVESVI)], was independently associated with all‐cause death [LVEDDI: hazard ratio (HR) per cm/m² 1.53, LVESDI: HR per cm/m² 1.65, LVEDVI: HR per 10 mL/m² 1.07, and LVESVI: HR per 10 mL/m² 1.10; all P values < 0.001], CV death (HR 1.68, 1.79, 1.09, and 1.12, respectively; all P values < 0.001), and HF hospitalization (HR 1.59, 1.79, 1.06, and 1.08, respectively; all P values < 0.001). No association was observed with myocardial infarction or stroke. The associations were independent of LV ejection fraction values, and incremental to them. LV volumes conferred additional predictive value over LV diameters.

Conclusions

Left ventricular enlargement is an independent predictor of CV events in patients with HFrEF and recommended HF treatment. LV dimensions should be considered in the risk assessment.

Cardiovascular magnetic resonance imaging of functional and microstructural changes of the heart in a longitudinal pig model of acute to chronic myocardial infarction

BACKGROUND

We examined the dynamic response of the myocardium to infarction in a longitudinal porcine study using relaxometry, functional as well as diffusion cardiovascular magnetic resonance (CMR). We sought to compare non contrast CMR methods like relaxometry and in-vivo diffusion to contrast enhanced imaging and investigate the link of microstructural and functional changes in the acute and chronically infarcted heart.

METHODS

CMR was performed on five myocardial infarction pigs and four healthy controls. In the infarction group, measurements were obtained 2 weeks before 90 min occlusion of the left circumflex artery, 6 days after ischemia and at 5 as well as 9 weeks as chronic follow-up. The timing of measurements was replicated in the control cohort. Imaging consisted of functional cine imaging, 3D tagging, T2 mapping, native as well as gadolinium enhanced T1 mapping, cardiac diffusion tensor imaging, and late gadolinium enhancement imaging.

RESULTS

Native T1, extracellular volume (ECV) and mean diffusivity (MD) were significantly elevated in the infarcted region while fractional anisotropy (FA) was significantly reduced. During the transition from acute to chronic stages, native T1 presented minor changes (< 3%). ECV as well as MD increased from acute to the chronic stages compared to baseline: ECV: 125 ± 24% (day 6) 157 ± 24% (week 5) 146 ± 60% (week 9), MD: 17 ± 7% (day 6) 33 ± 14% (week 5) 29 ± 15% (week 9) and FA was further reduced: - 31 ± 10% (day 6) - 38 ± 8% (week 5) - 36 ± 14% (week 9). T2 as marker for myocardial edema was significantly increased in the ischemic area only during the acute stage (83 ± 3 ms infarction vs. 58 ± 2 ms control p < 0.001 and 61 ± 2 ms in the remote area p < 0.001). The analysis of functional imaging revealed reduced left ventricular ejection fraction, global longitudinal strain and torsion in the infarct group. At the same time the transmural helix angle (HA) gradient was steeper in the chronic follow-up and a correlation between longitudinal strain and transmural HA gradient was detected (r = 0.59 with p < 0.05). Comparing non-gadolinium enhanced data T2 mapping showed the largest relative change between infarct and remote during the acute stage (+ 33 ± 4% day 6, with p = 0.013 T2 vs. MD, p = 0.009 T2 vs. FA and p = 0.01 T2 vs. T1) while FA exhibited the largest relative change between infarct and remote during the chronic follow-up (+ 31 ± 2% week 5, with p = N.S. FA vs. MD, p = 0.03 FA vs. T2 and p = 0.003 FA vs. T1). Overall, diffusion parameters provided a higher contrast (> 23% for MD and > 27% for FA) during follow-up compared to relaxometry (T1 17-18%/T2 10-20%).

CONCLUSION

During chronic follow-up after myocardial infarction, cardiac diffusion tensor imaging provides a higher sensitivity for mapping microstructural alterations when compared to non-contrast enhanced relaxometry with the added benefit of providing directional tensor information to assess remodelling of myocyte aggregate orientations, which cannot be otherwise assessed.

Bone-Marrow Stem Cells and Acellular Human Amniotic Membrane in a Rat Model of Heart Failure

Myocardial infarction (MI) remains the leading cause of cardiovascular death worldwide and a major cause of heart failure. Recent studies have suggested that cell-based therapies with bone marrow stem cells (BMSC) and human amniotic membrane (hAM) would recover the ventricular function after MI; however, the mechanisms underlying these effects are still controversial. Herein, we aimed to compare the effects of BMSC and hAM in a rat model of heart failure. MI was induced through coronary occlusion, and animals with an ejection fraction (EF) < 50% were included and randomized into three groups: control, BMSC, and hAM. The BMSC and hAM groups were implanted on the anterior ventricular wall seven days after MI, and a new echocardiographic analysis was performed on the 30th day, followed by euthanasia. The echocardiographic results after 30 days showed significant improvements on EF and left-ventricular end-sistolic and end-diastolic volumes in both BMSC and hAM groups, without significant benefits in the control group. New blood vessels, desmine-positive cells and connexin-43 expression were also elevated in both BMSC and hAM groups. These results suggest a recovery of global cardiac function with the therapeutic use of both BMSC and hAM, associated with angiogenesis and cardiomyocyte regeneration after 30 days.

Substrate Stiffness Influences Structural and Functional Remodeling in Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Novel treatment strategies for cardiac tissue regeneration are heading for the use of engineered cardiac tissue made from induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Despite the proven cardiogenic phenotype of these cells, a significant lack of structural and functional properties of mature myocytes prevents safe integration into the diseased heart. To date, maturation processes of cardiomyocytes remain largely unknown but may comprise biophysical cues from the immediate cell environment. Mechanosensing is one critical ability of cells to react to environmental changes. Accordingly, the surrounding substrate stiffness, comprised of extracellular matrix (ECM), cells, and growth surface, critically influences the myocyte's physiology, as known from deleterious remodeling processes in fibrotic hearts. Conversely, the mechanical properties during culture of iPSC-CMs may impact on their structural and functional maturation. Here, we tested the hypothesis that the environmental stiffness influences structural and functional properties of iPSC-CMs and investigated the effect of different substrate stiffnesses on cell contractility, excitation-contraction (EC) coupling, and intercellular coupling. Culture surfaces with defined stiffnesses ranging from rigid glass with 25GPa to PDMS of physiological softness were coated with ECM proteins and seeded with murine iPSC-CMs. Using confocal imaging, cardiac protein expression was assessed. Ca²⁺ handling and contractile properties were analyzed on different substrate stiffnesses. Intercellular coupling via gap junctions was investigated by fluorescence recovery after photobleaching (FRAP). Our data revealed greater organization of L-type Ca²⁺ channels and ryanodine receptors and increased EC-coupling gain, demonstrating structural and functional maturation in cells grown on soft surfaces. In addition, increased shortening and altered contraction dynamics revealed increased myofilament Ca²⁺ sensitivity in phase-plane loops. Moreover, connexin 43 expression was significantly increased in iPSC-CMs grown on soft surfaces leading to improved intercellular coupling. Taken together, our results demonstrate that soft surfaces with stiffnesses in the physiological range improve the expression pattern and interaction of cardiac proteins relevant for EC-coupling. In parallel, soft substrates influence contractile properties and improve intercellular coupling in iPSC-CMs. We conclude that the mechanical stiffness of the cell environment plays an important role in driving iPSC-CMs toward further maturation by inducing adaptive responses.

Machine Learning-Derived Echocardiographic Phenotypes Predict Heart Failure Incidence in Asymptomatic Individuals

OBJECTIVES

This study sought to identify homogenous echocardiographic phenotypes in community-based cohorts and assess their association with outcomes.

BACKGROUND

Asymptomatic cardiac dysfunction leads to a high risk of long-term cardiovascular morbidity and mortality; however, better echocardiographic classification of asymptomatic individuals remains a challenge.

METHODS

Echocardiographic phenotypes were identified using K-means clustering in the first generation of the STANISLAS (Yearly non-invasive follow-up of Health status of Lorraine insured inhabitants) cohort (N = 827; mean age: 60 ± 5 years; men: 48%), and their associations with vascular function and circulating biomarkers were also assessed. These phenotypes were externally validated in the Malmö Preventive Project cohort (N = 1,394; mean age: 67 ± 6 years; men: 70%), and their associations with the composite of cardiovascular mortality (CVM) or heart failure hospitalization (HFH) were assessed as well.

RESULTS

Three echocardiographic phenotypes were identified as "mostly normal (MN)" (n = 334), "diastolic changes (D)" (n = 323), and "diastolic changes with structural remodeling (D/S)" (n = 170). The D and D/S phenotypes had similar ages, body mass indices, cardiovascular risk factors, vascular impairments, and diastolic function changes. The D phenotype consisted mainly of women and featured increased levels of inflammatory biomarkers, whereas the D/S phenotype, consisted predominantly of men, displayed the highest values of left ventricular mass, volume, and remodeling biomarkers. The phenotypes were predicted based on a simple algorithm including e', left ventricular mass and volume (e'VM algorithm). In the Malmö cohort, subgroups derived from e'VM algorithm were significantly associated with a higher risk of CVM and HFH (adjusted HR in the D phenotype = 1.87; 95% CI: 1.04 to 3.37; adjusted HR in the D/S phenotype = 3.02; 95% CI: 1.71 to 5.34).

CONCLUSIONS

Among asymptomatic, middle-aged individuals, echocardiographic data-driven classification based on the simple e'VM algorithm identified profiles with different long-term HF risk. (4th Visit at 17 Years of Cohort STANISLAS-Stanislas Ancillary Study ESCIF [STANISLASV4]; NCT01391442).

The Hippo pathway regulates density-dependent proliferation of iPSC-derived cardiac myocytes

Inducing cardiac myocytes to proliferate is considered a potential therapy to target heart disease, however, modulating cardiac myocyte proliferation has proven to be a technical challenge. The Hippo pathway is a kinase signaling cascade that regulates cell proliferation during the growth of the heart. Inhibition of the Hippo pathway increases the activation of the transcription factors YAP/TAZ, which translocate to the nucleus and upregulate transcription of pro-proliferative genes. The Hippo pathway regulates the proliferation of cancer cells, pluripotent stem cells, and epithelial cells through a cell-cell contact-dependent manner, however, it is unclear if cell density-dependent cell proliferation is a consistent feature in cardiac myocytes. Here, we used cultured human iPSC-derived cardiac myocytes (hiCMs) as a model system to investigate this concept. hiCMs have a comparable transcriptome to the immature cardiac myocytes that proliferate during heart development in vivo. Our data indicate that a dense syncytium of hiCMs can regain cell cycle activity and YAP expression and activity when plated sparsely or when density is reduced through wounding. We found that combining two small molecules, XMU-MP-1 and S1P, increased YAP activity and further enhanced proliferation of low-density hiCMs. Importantly, these compounds had no effect on hiCMs within a dense syncytium. These data add to a growing body of literature that link Hippo pathway regulation with cardiac myocyte proliferation and demonstrate that regulation is restricted to cells with reduced contact inhibition.

[Left ventricular global function index as a predictor of adverse cardiovascular events in patients with acute coronary syndrome]

Aim      To evaluate the prognostic significance of the left ventricular global function index (LV GFI) in patients with acute coronary syndrome (ACS) using echocardiography (EchoCG).Material and methods             The LV GFI is an index that integrates LV cavity volumes, stroke volume, and myocardial volume. This study included 2169 patients with ACS (1340 (61.8%) men) aged 64.1±12.6 years from two observational multicenter studies, ORACLE I and ORACLE II. 1800 (83 %) cases were associated with increased concentrations of myocardial injury markers, including 826 (38.1 %) cases of ST segment elevation myocardial infarction (MI). The observation was started on the 10th day of clinical condition stabilization and lasted for one year. EchoCG was performed with evaluation of LV GFI, which was calculated as a ratio of LV stroke volume to LV global volume. The LV global volume was calculated as a sum of mean LV cavity volume (LV end-diastolic volume + LV end-systolic volume / 2) and LV myocardial volume.Results The main outcome of the study was all-cause death (n=193); recurrent coronary complications (n=253) were analyzed separately. The only EchoCG parameter indicating an adverse outcome during the one-year follow-up was a LV GFI decrease to below 22.6 % with a sensitivity of 72 % and a specificity of 60% (area under the curve, AUC=0.63). A LV GFI &lt;22.6 % was an independent predictor of all-cause death (p=0.019) along with age (p=0.0001), history of MI (p=0.034), and presence of heart failure (HF) (p=0.044), diabetes mellitus (p=0.012), and peripheral atherosclerosis (p=0.001). The LV GFI &lt;22.6 %, (p=0.044), heart rate upon discharge from the hospital (p=0.050), history of MI (p=0.006), presence of HF (p=0.014), and peripheral atherosclerosis (p=0.001) were also independent predictors for recurrent coronary complications. Decreased LV GFI was associated with the risk of fatal outcomes independent of the LV ejection fraction at baseline.Conclusion      In patients with ACS, the left ventricular global function index is an independent predictor for all-cause death and recurrent coronary complications and may be used for risk stratification.

Traditional Chinese medicine for acute coronary syndrome: A meta-analysis of clinical manifestations and objective indicators

BACKGROUND

Modern clinical trials and experimental researches of traditional Chinese medicine (TCM) have been conducted for decades and provided support for the prevention and treatment of acute coronary syndrome (ACS). However the level of evidence and the proper application of TCM were still barely satisfactory.

METHODS

In this study, we divided ACS into 3 different stages, including unstable angina, acute myocardial infarction, and post myocardial infarction. Then we systematically reviewed and meta-analyzed the existing randomized controlled trials on both clinical manifestations and objective indicators, in these 3 aspects.

RESULTS

The results indicate that TCM can both improve the clinical manifestations and ameliorate the objective parameters in different courses of ACS, including C-reactive protein in unstable angina, left ventricular ejection fraction in acute myocardial infarction and post myocardial infarction. And the incidence of short-term cardiovascular events are lower in TCM intervention group. Some of the improvements lead to potential long-term benefits.

CONCLUSION

TCM treatment is beneficial to different courses of ACS. To acquire more solid and comprehensive evidence of TCM in treating ACS, more rigorously designed randomized controlled trials with longer follow-up duration are warranted.

Genetic blockade of lymphangiogenesis does not impair cardiac function after myocardial infarction

In recent decades, treatments for myocardial infarction (MI), such as stem and progenitor cell therapy, have attracted considerable scientific and clinical attention but failed to improve patient outcomes. These efforts indicate that more rigorous mechanistic and functional testing of potential MI therapies is required. Recent studies have suggested that augmenting post-MI lymphatic growth via VEGF-C administration improves cardiac function. However, the mechanisms underlying this proposed therapeutic approach remain vague and untested. To more rigorously test the role of lymphatic vessel growth after MI, we examined the post-MI cardiac function of mice in which lymphangiogenesis had been blocked genetically by pan-endothelial or lymphatic endothelial loss of the lymphangiogenic receptor VEGFR3 or global loss of the VEGF-C and VEGF-D ligands. The results obtained using all three genetic approaches were highly concordant and demonstrated that loss of lymphatic vessel growth did not impair left ventricular ejection fraction two weeks after MI in mice. We observed a trend toward excess fluid in the infarcted region of the left ventricle, but immune cell infiltration and clearance were unchanged with loss of expanded lymphatics. These studies refute the hypothesis that lymphangiogenesis contributes significantly to cardiac function after MI, and suggest that any effect of exogenous VEGF-C is likely to be mediated by non-lymphangiogenic mechanisms.

Potential Therapeutic Benefits of Sodium-Glucose Cotransporter 2 Inhibitors in the Context of Ischemic Heart Failure: A State-Of-The-Art Review

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a class of anti-diabetic agents that block the reabsorption of glucose in the proximal convoluted tubule of the nephron, thereby contributing to glycosuria and lowering blood glucose levels. SGLT2 inhibitors have been associated with improved cardiovascular outcomes in patients with diabetes, including a reduced risk of cardiovascular death and hospitalizations for heart failure. Recently, DAPA-HF and EMPEROR REDUCED trials showed the beneficial cardiovascular effect of SGLT2 inhibitors in patients with heart failure with consistently reduced ejection fraction (HFrEF) regardless of the presence of diabetes. Moreover, some exploratory studies suggested that these drugs improve Left Ventricular (LV) systolic function and oppose LV adverse remodeling in patients with HFrEF. However, the exact mechanisms that mediated for this benefit are not fully understood. Beyond glycemic control, enhanced natriuresis, increased erythropoiesis, improved endothelial function, changes in myocardial metabolism, anti-inflammatory and anti-oxidative properties may all play an active role in SGLT2 inhibitors' cardiovascular benefits. A deep understanding of the pathophysiological interplay is key to define which HF phenotype could benefit more from SGLT2 inhibitors. Current clinical evidence on the comparison of different HF etiologies is limited to posthoc subgroup analysis of DAPA-HF and EMPEROR-REDUCED, which showed similar outcomes in patients with or without ischemic HF. On the other hand, in earlier studies of patients suffering from diabetes, rates of classic ischemic endpoints, such as myocardial infarction, stroke or coronary revascularization, did not differ between patients treated with SGLT2 inhibitors or placebo. The aim of this review is to discuss whether SGLT2 inhibitors may improve prognosis in patients with ischemic HF, not only in terms of reducing re-hospitalizations and improving left ventricular function but also by limiting coronary artery disease progression and ischemic burden.

Calcium and integrin binding protein 1 (CIB1) induces myocardial fibrosis in myocardial infarction via regulating the PI3K/Akt pathway

Myocardial infarction (MI) is a severe coronary artery disease resulted from substantial and sustained ischemia. Abnormal upregulation of calcium and integrin binding protein 1 (CIB1) has been found in several cardiovascular diseases. In this study, we established a mouse model of MI by permanent ligation of the left anterior descending coronary artery. CIB1 was upregulated in the heart of MI mice. Notably, CIB1 knockdown by intramuscular injection of lentivirus-mediated short hairpin RNA (shRNA) targeting Cib1 improved cardiac function and attenuated myocardial hypertrophy and infarct area in MI mice. MI-induced upregulation of α-SMA, vimentin, Collagen I, and Collagen III, which resulted in collagen production and myocardial fibrosis, were regressed by CIB1 silencing. In vitro, cardiac fibroblasts (CFs) isolated from mice were subjected to angiotensin II (Ang II) treatment. Inhibition of CIB1 downregulated the expression of α-SMA, vimentin, Collagen I, and Collagen III in Ang II-treated CFs. Moreover, CIB1 knockdown inhibited Ang II-induced phosphorylation of PI3K-p85 and Akt in CFs. The effect of CIB1 knockdown on Ang II-induced cellular injury was comparable to that of LY294002, a specific inhibitor of the PI3K/Akt pathway. We demonstrated that MI-induced cardiac hypertrophy, myocardial fibrosis, and cardiac dysfunction might be attributed to the upregulation of CIB1 in MI mice. Downregulation of CIB1 alleviated myocardial fibrosis and cardiac dysfunction by decreasing the expression of α-SMA, vimentin, Collagen I, and Collagen III via inhibiting the PI3K/Akt pathway. Therefore, CIB1 may be a potential target for MI treatment.

Role of high-density lipoproteins in cardioprotection and in reverse remodeling: Therapeutic implications

Cardioprotection includes all mechanisms that contribute to preservation of the heart by reducing or even preventing myocardial damage. High-density lipoproteins (HDLs) are circulating multimolecular platforms that exert a multitude of effects on cardiomyocytes and nonmyocyte cells in the myocardium leading to preservation of cardiac structure and function. Animal intervention studies applying HDL-targeted therapies have provided consistent evidence that HDLs protect against ischemia-reperfusion injury, leading to smaller myocardial infarctions, and that HDLs attenuate infarct expansion and cardiac remodeling post-myocardial infarction. These beneficial effects of HDLs are not restricted to prevention of development of ischemic cardiomyopathy but also apply to prevention of pathological hypertrophy and adverse remodeling in the presence of diabetes or in the presence of pressure overload. Moreover, HDLs can induce reverse remodeling characterized by a reduction of cardiac hypertrophy, a decrease of myocardial fibrosis, a regression of capillary rarefaction, and a restoration of cardiac function. HDL-targeted interventions are an effective treatment for heart failure in animal models. In conclusion, whereas protective effects of HDLs on coronary arteries remain essentially unproven till now, the potential for clinical translation of HDL-targeted interventions in prevention of cardiomyopathy and in treatment of heart failure is supported by consistent evidence from animal intervention studies.

A novel substrate based on electrospun polyurethane nanofibers and electrosprayed polyvinyl alcohol microparticles for recombinant human erythropoietin delivery

After myocardial infarction caused by a heart attack, endothelial cells need to be preserved in order to regenerate new capillaries. Moreover, sufficient mechanical support is necessary for the infarcted myocardium to pump the blood. Herein, we designed a novel substrate containing polyurethane (PU) nanofibrous layers and recombinant human erythropoietin (rhEPO)-loaded microparticles for both controlled releases of rhEPO and mechanical support of myocardium. In this system, the single-layer (SL) and double-layer (DL) PU nanofibers were electrospun, and then microparticles with different rhEPO:polyvinyl alcohol (PVA) ratios were electrosprayed on the layers. The in vitro release behavior of rhEPO from SL substrates was not satisfactory, and then the study focused on DL patches in which the release profile was in accordance with Korsmeyer-Peppas model. The release exponent of 0.89 for the DL PU/120PVA:1rhEPO represented zero-order release. The results inferred that these substrates possessed highly tailored mechanical properties; Young's modulus and ultimate tensile strength of the substrates were 74-172 kPa and 7.4-9.9 MPa, respectively. The rhEPO release from the substrates was leading to the proper adhesion of endothelial cells and more than 95% cell viability. The results indicated that the patch of elastic nanofibers and microparticles offered a potential substrate for simultaneous rhEPO delivery to endothelial cells and also mechanically supporting the infarcted myocardium.

Risk Prediction Model Based on Biomarkers of Remodeling in Patients with Acute Anterior ST-Segment Elevation Myocardial Infarction

Background

The aim of the present study was to develop a risk prediction model in patients with acute anterior ST-segment elevation myocardial infarction (STEMI).

Material/Methods

Clinical data from 333 patients with acute anterior STEMI were retrospectively analyzed. Clinical echocardiographic and angiographic data from patients with left ventricular remodeling (LVR) and those without LVR were compared. Factors that influenced risk were identified using multivariate logistic regression analysis. The area under the curve (AUC) of the receiver operating characteristic curve was used to assess the diagnostic performance of the model.

Results

After 6-month follow-up, 135 of the patients experienced LVR (LVR group), whereas 198 did not (non-LVR group). Results of multivariate analysis showed that the number of stenosed coronary vessels, left ventricular end-diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), transforming growth factor-beta (TGF-β) at admission, and cardiac troponin I 3 days after admission (3-d cTnI) were all factors predictive of LVR in patients with acute anterior STEMI (all P<0.05). The established prediction model was Y=−20.639+0.711×number of stenosed coronary vessels + 0.137×LVEDV-0.129×LVEF+0.026×TGF-β at admission + 0.162×3-d cTnI. The estimated AUC of this model was 0.978 (95% confidence interval [CI] 0.955–0.991), significantly superior to the single-factor numbers for stenosed coronary vessel of 0.650 (95% CI 0.597–0.702), LVEDV of 0.876 (95% CI 0.836–0.910), LVEF of 0.684 (95% CI 0.631–0.734), TGF-β at admission of 0.696 (95% CI 0.644–0.745), cTnI at admission of 0.913 (95% CI 0.877–0.941), and 3-d cTnI of 0.945 (95% CI 0.914–0.967).

Conclusions

The established model had excellent diagnostic accuracy for predicting LVR in patients with acute anterior STEMI.

Monoterpenes and their derivatives as agents for cardiovascular disease management: A systematic review and meta-analysis

BACKGROUND

Monoterpenes are one of the most studied plant's secondary metabolites, they are found abundantly in essential oils of aromatic plants. They also have a great range of pharmacological properties, such as antihypertensive, bradycardic, antiarrhythmic and hypotensive. In the face of the burden caused by cardiovascular disease (CVDs) worldwide, studies using monoterpenes to assess their cardiovascular effects have increased over the years.

PURPOSE

This systematic review aimed to summarize the use of monoterpenes in animal models of any CVDs.

METHODS

PubMed, SCOPUS, LILACS and Web of Science databases were used to search for articles that used monoterpenes, in any type of administration, to treat or prevent CVDs in animal models. The PRISMA guidelines were followed. Two independent researchers extracted main characteristics of studies, methods and outcomes. Data obtained were analyzed qualitatively and quantitatively.

RESULTS

At the ending of the search process, 33 articles were selected for the systematic review. Of these, 17 articles were included in the meta-analysis. A total of 16 different monoterpenes were found for the treatment of hypertension, myocardial infarction, pulmonary hypertension, cardiac hypertrophy and arrhythmia. The main actions include hypotension, bradycardia, vasodilatation, antiarrhythmic, and antioxidant and antiapoptotic properties. From our data, it can be suggested that monoterpenes may be a significant source for new drug development. However, there is still a need to apply these knowledge into clinical research and a long path to pursue before putting them in the market.

CONCLUSION

The variability of cardiovascular effects demonstrated by the monoterpenes highlighted them as a promising candidates for treatment or prevention of CVDs. Nevertheless, studies that investigate their biological sites of action needs to be further encouraged.

Engineering the Cellular Microenvironment of Post-infarct Myocardium on a Chip

Myocardial infarctions are one of the most common forms of cardiac injury and death worldwide. Infarctions cause immediate necrosis in a localized region of the myocardium, which is followed by a repair process with inflammatory, proliferative, and maturation phases. This repair process culminates in the formation of scar tissue, which often leads to heart failure in the months or years after the initial injury. In each reparative phase, the infarct microenvironment is characterized by distinct biochemical, physical, and mechanical features, such as inflammatory cytokine production, localized hypoxia, and tissue stiffening, which likely each contribute to physiological and pathological tissue remodeling by mechanisms that are incompletely understood. Traditionally, simplified two-dimensional cell culture systems or animal models have been implemented to elucidate basic pathophysiological mechanisms or predict drug responses following myocardial infarction. However, these conventional approaches offer limited spatiotemporal control over relevant features of the post-infarct cellular microenvironment. To address these gaps, Organ on a Chip models of post-infarct myocardium have recently emerged as new paradigms for dissecting the highly complex, heterogeneous, and dynamic post-infarct microenvironment. In this review, we describe recent Organ on a Chip models of post-infarct myocardium, including their limitations and future opportunities in disease modeling and drug screening.

Dapagliflozin attenuates arrhythmic vulnerabilities by regulating connexin43 expression via the AMPK pathway in post-infarcted rat hearts

We have demonstrated that dapagliflozin, a sodium-glucose cotransporter (SGLT) 2 inhibitor, attenuates reactive oxygen species (ROS) production. Connexin43 playing a role in ventricular arrhythmia is sensitive to redox status. No data are available on the effects of dapagliflozin on arrhythmogenesis. This study was to determine whether dapagliflozin attenuated arrhythmias through modulating AMP-activated protein kinase (AMPK)/free radicals-induced connexin43 after myocardial infarction. After coronary ligation, normoglycemic male Wistar rats were randomized to either vehicle or dapagliflozin (0.1 mg/kg per day) for 4 weeks. Myocardial ROS levels were significantly increased (p < 0.05) and connexin43 levels were substantially decreased after myocardial infarction (p < 0.05). Dapagliflozin administration was associated with increased SGLT1, attenuated ROS and increased connexin43 levels in myocardium (all p < 0.05). During programmed electrical stimulation, arrhythmic severity was significantly improved in the dapagliflozin-treated infarcted rats than those in the vehicle-treated infarcted rats (p < 0.05). Dapagliflozin significantly increased AMPK phosphorylation compared to vehicle after infarction (p < 0.05). Inhibition of AMPK signaling by SBI-0206965 prevented increased SGLT1 and blocked the effects of dapagliflozin on attenuated ROS levels and increased connexin43 phosphorylation (all p < 0.05). SGLT1 inhibited by KGA-2727 showed attenuated ROS levels and increased connexin43 phosphorylation (both p < 0.05) although AMPK phosphorylation was not changed, implying SGLT1 activation was mediated by AMPK in dapagliflozin-treated hearts. Dapagliflozin-treated hearts had significantly increased connexin43 phosphorylation (p < 0.05), which was significantly decreased after adding 3-morpholinosydnonimine (p < 0.05). These data indicate that clinically-relevant dapagliflozin concentrations decreased free radicals content and increased connexin43 levels through AMPK-dependent and SGLT1-independent mechanisms, which attenuated ventricular arrhythmias in the normoglycemic infarcted rats.

Downregulation of IFIT3 relieves the inflammatory response and myocardial fibrosis of mice with myocardial infarction and improves their cardiac function

Myocardial infarction (MI) is a common cardiovascular disease with high morbidity and mortality. In this study, we explored the role of interferon-induced protein with tetratricopeptide repeats 3 (IFIT3) in MI. MI was induced by ligation of the left anterior descending coronary artery. Lentivirus-mediated RNA interference of IFIT3 expression was performed by tail vein injection 72 h before MI modeling. Cardiac injury indexes and inflammatory response were examined 3 days after MI. Cardiac function indexes, infarct size, and cardiac fibrosis were assessed 4 weeks after MI. IFIT3 expression was upregulated in myocardial tissues at both 3 days and 4 weeks after MI. Knockdown of IFIT3 significantly relieved the myocardial injury, as evidenced by the decrease in serum levels of cTnI and CK-MB. In addition, IFIT3 knockdown significantly reduced the number of CD68⁺ macrophages and the levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α, indicating that the inflammatory response was relieved. Moreover, IFIT3 silencing also significantly improved cardiac function and reduced infarct size, myocardial fibrosis, and collagen content in mice with MI. Mechanically, the present study showed that the activation of the mitogen-activated protein kinase (MAPK) pathway was observed in myocardial tissues of MI mice, which was blocked by IFIT3 knockdown, as indicated by the decreased phosphorylation of JNK, p-38, and ERK. Collectively, our results revealed the role of IFIT3 in the inflammatory response and myocardial fibrosis after MI, indicating that IFIT3 might be a potential target for MI treatment.

Comprehensive assessment of myocardial remodeling in ischemic heart disease by synchrotron propagation based X-ray phase contrast imaging

Cardiovascular research is in an ongoing quest for a superior imaging method to integrate gross-anatomical information with microanatomy, combined with quantifiable parameters of cardiac structure. In recent years, synchrotron radiation-based X-ray Phase Contrast Imaging (X-PCI) has been extensively used to characterize soft tissue in detail. The objective was to use X-PCI to comprehensively quantify ischemic remodeling of different myocardial structures, from cell to organ level, in a rat model of myocardial infarction. Myocardial infarction-induced remodeling was recreated in a well-established rodent model. Ex vivo rodent hearts were imaged by propagation based X-PCI using two configurations resulting in 5.8 µm and 0.65 µm effective pixel size images. The acquired datasets were used for a comprehensive assessment of macrostructural changes including the whole heart and vascular tree morphology, and quantification of left ventricular myocardial thickness, mass, volume, and organization. On the meso-scale, tissue characteristics were explored and compared with histopathological methods, while microstructural changes were quantified by segmentation of cardiomyocytes and calculation of cross-sectional areas. Propagation based X-PCI provides detailed visualization and quantification of morphological changes on whole organ, tissue, vascular as well as individual cellular level of the ex vivo heart, with a single, non-destructive 3D imaging modality.

Intravenous ferric carboxymaltose does not provide benefits in reperfused acute myocardial infarction in the rat with normal iron status

BACKGROUND

Iron deficiency has been implicated in the pathophysiology of heart failure and myocardial ischemia and reperfusion injury. Moreover, reperfused heart seems to lose iron, thus even subjects with normal iron status could benefit from iron therapy. Impaired mitochondrial respiration and energy starvation may be among possible consequences of myocardial iron deficiency. So far no attempts have been made to treat acute coronary syndromes with iron. Thus our aim was to verify the hypothesis that intravenous iron therapy given during reperfusion of an acute myocardial infarction will reduce left ventricular remodeling and hemodynamic abnormalities in a 2-month follow-up as well as early mitochondrial dysfunction and mortality, in the rat with normal iron status.

METHODS AND RESULTS

A single dose of ferric carboxymaltose was administered intravenously at 30 min of reperfusion following 30 min of ischemia in the rat model of myocardial infarction. Ventricular arrhythmias were monitored using a telemetric system, activity of mitochondrial enzymes was assessed using spectrophotometry, serum markers of oxidative stress and inflammation were determined and left ventricular function and remodeling were monitored using echocardiography and pressure-volume loops. Intravenous iron therapy did not affect post-myocardial infarction mortality, left ventricular size or function, ventricular arrhythmias, activity of mitochondrial respiratory chain, oxidative stress or markers of inflammation, but was not associated with any adverse effects.

CONCLUSIONS

Although ferric carboxymaltose given at reperfusion was safe, it was ineffective in this model of reperfused myocardial infarction in the rat with normal iron status.

Desmin aggrephagy in rat and human ischemic heart failure through PKCζ and GSK3β as upstream signaling pathways

Post-translational modifications of cardiac proteins could participate to left contractile dysfunction resulting in heart failure. Using a rat model of ischemic heart failure, we showed an accumulation of phosphorylated desmin leading to toxic aggregates in cardiomyocytes, but the cellular mechanisms are unknown. The same rat model was used to decipher the kinases involved in desmin phosphorylation and the proteolytic systems present in rat and human failing hearts. We used primary cultures of neonate rat cardiomyocytes for testing specific inhibitors of kinases and for characterizing the autophagic processes able to clear desmin aggregates. We found a significant increase of active PKCζ, no modulation of ubitiquitin-proteasome system, a defect in macroautophagy, and an activation of chaperone-mediated autophagy in heart failure rats. We validated in vitro that PKCζ inhibition induced a significant decrease of GSK3β and of soluble desmin. In vitro activation of ubiquitination of proteins and of chaperone-mediated autophagy is able to decrease soluble and insoluble forms of desmin in cardiomyocytes. These data demonstrate a novel signaling pathway implicating activation of PKCζ in desmin phosphorylation associated with a defect of proteolytic systems in ischemic heart failure, leading to desmin aggrephagy. Our in vitro data demonstrated that ubiquitination of proteins and chaperone-mediated autophagy are required for eliminating desmin aggregates with the contribution of its chaperone protein, α-crystallin Β-chain. Modulation of the kinases involved under pathological conditions may help preserving desmin intermediate filaments structure and thus protect the structural integrity of contractile apparatus of cardiomyocytes by limiting desmin aggregates formation.

Left ventricular mechanical dispersion in ischaemic cardiomyopathy: association with myocardial scar burden and prognostic implications

AIMS

Left ventricular (LV) mechanical dispersion (MD) may result from heterogeneous electrical conduction and is associated with adverse events. The present study investigated (i) the association between LV MD and the extent of LV scar as assessed with contrast-enhanced cardiac magnetic resonance (CMR) and (ii) the prognostic implications of LV MD in patients after ST-segment elevation myocardial infarction.

METHODS AND RESULTS

LV MD was calculated by echocardiography and myocardial scar was analysed on CMR data retrospectively. Infarct core and border zone were defined as ≥50% and 35-50% of maximal signal intensity, respectively. Patients were followed for the occurrence of the combined endpoint (all-cause mortality and appropriate implantable cardioverter-defibrillator therapy). In total, 96 patients (87% male, 57 ± 10 years) were included. Median LV MD was 53.5 ms [interquartile range (IQR) 43.4-62.8]. On CMR, total scar burden was 11.4% (IQR 3.8-17.1%), infarct core tissue 6.2% (IQR 2.0-12.7%), and border zone was 3.5% (IQR 1.5-5.7%). Correlations were observed between LV MD and infarct core (r = 0.517, P < 0.001), total scar burden (r = 0.497, P < 0.001), and border zone (r = 0.298, P = 0.003). In total, 14 patients (15%) reached the combined endpoint. Patients with LV MD >53.5 ms showed higher event rates as compared to their counterparts. Finally, LV MD showed the highest area under the curve for the prediction of the combined endpoint.

CONCLUSION

LV MD is correlated with LV scar burden. In addition, patients with prolonged LV MD showed higher event rates. Finally, LV MD provided the highest predictive value for the combined endpoint when compared with other parameters.

Impact of COVID-19 pandemic lockdown on myocardial infarction care

The aim of this study was to evaluate the impact of the COVID-19 pandemic lockdown on acute myocardial infarction (AMI) care, and to identify underlying stressors in the German model region for complete AMI registration. The analysis was based on data from the population-based KORA Myocardial Infarction Registry located in the region of Augsburg, Germany. All cases of AMI (n = 210) admitted to one of four hospitals in the city of Augsburg or the county of Augsburg from February 10th, 2020, to May 19, 2020, were included. Patients were divided into three groups, namely pre-lockdown, strict lockdown, and attenuated lockdown period. An additional survey was conducted asking the patients for stress and fears in the 4 weeks prior to their AMI. The AMI rate declined by 44% in the strict lockdown period; in the attenuated lockdown period the rate was 17% lower compared to the pre-lockdown period. The downward trend in AMI rates during lockdown was seen in STEMI and NSTEMI patients, and independent of sex and age. The door-to-device time decreased by 70–80% in the lockdown-periods. In the time prior to the infarction, patients felt stressed mainly due to fear of infection with Sars-CoV-2 and less because of the restrictions and consequences of the lockdown. A strict lockdown due to the Covid-19 pandemic had a marked impact on AMI care even in a non-hot-spot region with relatively few cases of COVID-19. Fear of infection with the virus is presumably the main reason for the drop in hospitalizations due to AMI.

Expedient assessment of post-infarct remodeling by native cardiac magnetic resonance imaging in mice

Novel therapeutic strategies aiming at improving the healing process after an acute myocardial infarction are currently under intense investigation. The mouse model plays a central role for deciphering the underlying mechanisms on a molecular and cellular level. Therefore, we intended to assess in-vivo post-infarct remodeling as comprehensively as possible using an expedient native magnetic resonance imaging (MRI) in the two most prominent infarct models, permanent ligation (PL) of the left anterior descending artery (LAD) versus ischemia reperfusion (I/R). Mice were subjected to either permanent or transient (45 min) occlusion of the LAD. After 3 weeks, examinations were performed with a 7-Tesla small animal MRI system. Data analysis was performed with the freely available software Segment. PL resulted in a massive dilation of the left ventricle, accompanied by hypertrophy of the non-infarcted myocardium and a decline of contractile function. These effects were less pronounced following I/R compared to healthy animals. Single plane assessments were not sufficient to capture the specific differences of left ventricular (LV) properties between the two infarct models. Bulls-eye plots were found to be an ideal tool for qualitative LV wall assessment, whereas a multi-slice sector-based analysis of wall regions is ideal to determine differences in hypertrophy, lateral wall thinning and wall thickening on a quantitative level. We combine the use of polar map-based analysis of LV wall properties with volumetric measurements using simple CINE CMR imaging. Our strategy represents a versatile and easily available tool for serial assessment of the LV during the remodeling process. Our study contributes to a better understanding of the effects of novel therapies targeting the healing of damaged myocardium.

5-Methoxytryptophan attenuates postinfarct cardiac injury by controlling oxidative stress and immune activation

AIMS

Myocardial infarction (MI) remains a major cause of heart failure. 5-Methoxytryptophan (5-MTP), a 5-methoxyindole metabolite of L-tryptophan, exerts anti-inflammatory and antifibrotic effects, but MI impairs the biosynthesis of cardiac 5-MTP. Therefore, we evaluated the effect of exogenous 5-MTP administration on rescuing post-MI cardiac injury.

METHODS AND RESULTS

After a detailed pharmacokinetic analysis of 5-MTP, Sprague Dawley rats that had undergone left anterior descending coronary artery ligation received intraperitoneal administration of either 17 mg/kg 5-MTP or saline at 0.5 and 24 h after MI. Cardiac systolic function, infarction size, and fibrosis were evaluated using echocardiography, triphenyltetrazolium chloride staining, and Masson trichrome staining, respectively. Myocardial apoptosis was analyzed by staining for caspase-3 and cardiac troponin I. 5-MTP treatment decreased the infarct area and myocardial apoptosis; attenuated systolic dysfunction and left ventricular dilatation; and reduced cardiomyocyte hypertrophy, myocardial fibrosis, and infarct expansion. Crucially, 5-MTP alleviated oxidative stress by preserving mitochondrial antioxidant enzymes and downregulating reactive oxygen species-generating NADPH oxidase isoforms and endothelin-1. Consequently, 5-MTP-treated MI rat hearts exhibited lower levels of chemokines and cytokines, namely interleukin (IL)-1β, IL-18, IL-6, C-C motif chemokine ligand (CCL)-2, and CCL5, accompanied by reduced infiltration of CD11b⁺ cells and CD4⁺ T cells. Notably, 5-MTP protected against H₂O₂-induced damage in HL-1 cardiomyocytes and human umbilical vein endothelial cells in vitro.

CONCLUSION

5-MTP prevented post-MI cardiac injury by promoting mitochondrial stabilization and controlling redox imbalance. This cytoprotective effect ameliorated macrophage and T-cell infiltration, thus reducing the infarct size, attenuating fibrosis, and restoring myocardial function.

COPD maintenance medication is linked to left atrial size: Results from the COSYCONET cohort

BACKGROUND

Lung function impairment in COPD is known to be related to reductions of left heart size, while short-term interventional trials with bronchodilators showed positive effects on cardiac parameters. We investigated whether COPD maintenance therapy has analogous long-term effects.

METHODS

Pooled data of GOLD grade 1-4 patients from visits 1 and 3 (1.5 y apart) of the COSYCONET cohort were used. Medication was categorized as use of ICS, LABA + ICS, LABA + LAMA and triple therapy (LABA + LAMA + ICS), contrasting "always" versus "never". Echocardiographic parameters comprised left ventricular end-diastolic and -systolic diameter (LVEDD, LVESD), ejection fraction (LVEF) and left atrial diameter (LA). Associations were identified by multiple regression analysis, as well as propensity score analysis.

RESULTS

Overall, 846 patients (mean age 64.5 y; 41% female) were included, 53% using ICS at both visits, 51% LABA + ICS, 56% LABA + LAMA, 40% LABA + LAMA + ICS (triple) therapy. Conversely, 30%, 32%, 28% and 42% had no ICS, LABA + ICS, LABA + LAMA or triple therapy, respectively, at both visits. Among echocardiographic measures, only LA showed statistically significant associations (increases) with medication, whereby significant effects were linked to ICS, LABA + ICS and LABA + LAMA (p < 0.05 each, "always" versus "never") and propensity score analyses underlined the role of LABA + LAMA.

CONCLUSIONS

In this observational study, COPD maintenance therapy, especially LABA + LAMA, was linked to left atrial size, consistent with the results of short-term interventional trials. These findings suggest that maintenance medication for COPD does not only improve lung function and patient reported outcomes but may also have an impact on the cardiovascular system.

TRIAL REGISTRATION

NCT01245933.

Prognostic Role of High Sensitivity C-Reactive Protein in Patients With Acute Myocardial Infarction

Background: High sensitivity CRP (hs-CRP) has attracted intense interest in risk assessment. We aimed to explore its prognostic value in patients with acute myocardial infarction (AMI).

Methods and Results: We enrolled 4,504 consecutive AMI patients in this prospective cohort study. The associations between hs-CRP levels with the incidence of in-hospital HF was evaluated by logistic regression analysis. The association between hs-CRP levels and the cumulative incidence of HF after hospitalization were evaluated by Fine-Gray proportional sub-distribution hazards models, accounting for death without HF as competing risk. Cox proportional hazards regression models were constructed to estimate the association between hs-CRP levels and the risk of all-cause mortality. Over a median follow-up of 1 year, 1,112 (24.7%) patients developed in-hospital HF, 571 (18.9%) patients developed HF post-discharge and 262 (8.2%) patients died. In the fully adjusted model, the risk of in-hospital heart failure (HF) [95% confidence intervals (CI)] among those patients with hs-CRP values in quartile 3 (Q3) and Q4 were 1.36 (1.05–1.77) and 1.41 (1.07–1.85) times as high as the risk among patients in Q1 (p trend < 0.001). Patients with hs-CRP values in Q3 and Q4 had 1.33 (1.00–1.76) and 1.80 times (1.37–2.36) as high as the risk of HF post-discharge compared with patients in Q1 respectively (p trend < 0.001). Patients with hs-CRP values in Q3 and Q4 had 1.74 (1.08–2.82) and 2.42 times (1.52–3.87) as high as the risk of death compared with patients in Q1 respectively (p trend < 0.001).

Conclusions: Hs-CRP was found to be associated with the incidence of in-hospital HF, HF post-discharge and all-cause mortality in patients with AMI.

Effect of Neprilysin Inhibition on Left Ventricular Remodeling in Patients With Asymptomatic Left Ventricular Systolic Dysfunction Late After Myocardial Infarction

BACKGROUND

Patients with left ventricular (LV) systolic dysfunction after myocardial infarction are at a high risk of developing heart failure. The addition of neprilysin inhibition to renin angiotensin system inhibition may result in greater attenuation of adverse LV remodeling as a result of increased levels of substrates for neprilysin with vasodilatory, antihypertrophic, antifibrotic, and sympatholytic effects.

METHODS

We performed a prospective, multicenter, randomized, double-blind, active-comparator trial comparing sacubitril/valsartan 97/103 mg twice daily with valsartan 160 mg twice daily in patients ≥3 months after myocardial infarction with a LV ejection fraction ≤40% who were taking a renin angiotensin system inhibitor (equivalent dose of ramipril ≥2.5 mg twice daily) and a β-blocker unless contraindicated or intolerant. Patients in New York Heart Association class ≥II or with signs and symptoms of heart failure were excluded. The primary outcome was change from baseline to 52 weeks in LV end-systolic volume index measured using cardiac magnetic resonance imaging. Secondary outcomes included other magnetic resonance imaging measurements of LV remodeling, change in NT-proBNP (N-terminal pro-B-type natriuretic peptide) and high-sensitivity cardiac troponin I, and a patient global assessment of change questionnaire.

RESULTS

From July 2018 to June 2019, we randomized 93 patients with the following characteristics: mean age, 60.7±10.4 years; median time from myocardial infarction, 3.6 years (interquartile range, 1.2-7.2); mean LV ejection fraction, 36.8%±7.1%; and median NT-proBNP, 230 pg/mL (interquartile range, 124-404). Sacubitril/valsartan, compared with valsartan, did not significantly reduce LV end-systolic volume index; adjusted between-group difference, -1.9 mL/m² (95% CI, -4.9 to 1.0); P=0.19. There were no significant between-group differences in NT-proBNP, high-sensitivity cardiac troponin I, LV end-diastolic volume index, left atrial volume index, LV ejection fraction, LV mass index, or patient global assessment of change.

CONCLUSIONS

In patients with asymptomatic LV systolic dysfunction late after myocardial infarction, treatment with sacubitril/valsartan did not have a significant reverse remodeling effect compared with valsartan. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03552575.

Large- and Medium-sized Arteries Remaining in Transmural Scar Distal to Permanent Coronary Ligation Undergo Neointimal Hyperplasia and Inward Remodeling

This study aimed to investigate the structural integrity and dynamic changes in chronically occluded residual arteries found in post-myocardial infarction (MI) scar. A transmural MI was induced in middle-aged, male Sprague-Dawley rats by left coronary artery ligation. The rats were euthanized 3 days and 1, 2, 4, 8, and 12 weeks after MI, and their hearts were processed into paraffin for histology, immunohistochemistry, and quantitative morphometry. It has been found that large- and medium-sized arteries were able to survive inside the transmural scars for 12 post-MI weeks. Furthermore, most residual arteries preserved their structural integrity for up to 2 weeks post-MI, but gradually all disused vessels had undergone neointimal hyperplasia and inward remodeling at later time periods. In addition, the replacement of vascular smooth muscle cells in the wall of residual arteries by extracellular matrix components led to a disruption of the vessel integrity and progressive obliteration of their lumen between 4 and 12 post-MI weeks. Taken together, this study demonstrate that residual arteries in post-infarcted region were capable of maintaining their structural integrity, including the patent lumen, during two post-MI weeks, suggesting that during this period they can be used as potential conduits for conceivable reflow of arterial blood within the scarred region of the heart.

Long-term prognosis analysis of PARACHUTE device implantation in patients with ischemic heart failure: a single-center experience of Chinese patients

BACKGROUND

Heart failure (HF) is one of the leading causes of mortality and morbidity. The PARACHUTE device is designed to partition for left ventricular (LV) apical aneurysm post extensive anterior myocardial infarction (MI). However, the long-term prognosis of the PARACHUTE device post-implantation is unclear.

METHODS

From November 2015 to April 2017, six subjects with New York Heart Association Classes II, III and IV ischemic HF, LV ejection fraction between (LVEF) 15 and 40%; and LV anterior apical aneurysm were enrolled in our center. The cumulative event rates for MI, hospitalization, and mortality were documented. Further assessment of LVEF, LV end-diastolic diameter (LVEDD), and estimated pulmonary artery pressure were determined by echocardiography core laboratory. For quantitative data comparison, paired t-test was employed.

RESULTS

Device implantation was successful in all six enrolled subjects, and acute device association adverse events were not observed. At 4.6 ± 1.7 years follow-up, major adverse cardiac events (MACEs) were found in 50% patients, and the survival rate was 86.7%. We observed that the LVEF was significantly elevated after deployment (46.00 ± 6.00% vs. 35.83 ± 1.47%, P = 0.009). Besides, the LVEDD elevated after MI (51.17 ± 3.71 vs. 62.83 ± 3.25, P < 0.001) was revealed, but the device sustained preserved LVEDD after implantation.

CONCLUSION

The PARACHUTE device is an alternative therapy for patients with severe LV maladaptive remodeling. However, the device seems to increase the HF ratio.

TRIAL REGISTRATION

NCT02240940.

Photobiomodulation Therapy on Myocardial Infarction in Rats: Transcriptional and Posttranscriptional Implications to Cardiac Remodeling

BACKGROUND AND OBJECTIVES

Induction of myocardial infarction (MI) in rats by occlusion of the left anterior descending coronary artery is an experimental model used in research to elucidate functional, structural, and molecular modifications associated with ischemic heart disease. Photobiomodulation therapy (PBMT) has become a therapeutic alternative by modulating various biological processes eliciting several effects, including anti-inflammatory and pro-proliferative actions. The main objective of this work was to evaluate the effect of PBMT in the modulation of transcriptional and post-transcriptional changes that occurred in myocardium signal transduction pathways after MI.

STUDY DESIGN/MATERIALS AND METHODS

Continuous wave (CW) non-thermal laser parameters were: 660 nm wavelength, power 15 mW, with a total energy of 0.9 J, fluence of 1.15 J/cm² , spot size of 0.785 cm² , and time of 60 seconds. Using in silico analysis, we selected and then, quantified the expression of messenger RNA (mRNA) of 47 genes of 9 signaling pathways associated with MI (angiogenesis, cell survival, hypertrophy, oxidative stress, apoptosis, extracellular matrix, calcium kinetics, cell metabolism, and inflammation). Messenger RNA expression quantification was performed in myocardial samples by polymerase chain reaction real-time array using TaqMan customized plates.

RESULTS

Our results evidenced that MI modified mRNA expression of several well-known biomarkers related to detrimental cardiac activity in almost all signaling pathways analyzed. However, PBMT reverted most of these transcriptional changes. More expressively, PBMT provoked a robust decrease in mRNA expression of molecules that participate in post-MI inflammation and ECM composition, such as IL-6, TNF receptor, TGFb1, and collagen I and III. Global microRNA (miRNA) expression analysis revealed that PBMT decreased miR-221, miR-34c, and miR-93 expressions post-MI, which are related to deleterious effects in cardiac remodeling.

CONCLUSION

Thus, the identification of transcriptional and post-transcriptional changes induced by PBMT may be used to interfere in the molecular dynamics of cardiac remodeling post-MI.

Left Ventricular Remodeling Risk Predicted by Two-Dimensional Speckle Tracking Echocardiography in Acute Myocardial Infarction Patients with Midrange or Preserved Ejection Fraction in Western Romania

Background

Patients with acute myocardial infarction (AMI) are at high risk for left ventricular (LV) remodeling and heart failure. We aimed to study whether LV strains (S) and strain rates (SR) could predict cardiac remodeling in patients with AMI having a midrange or preserved LV ejection fraction (EF) following a percutaneous coronary intervention (PCI) within the first 12 hours from the onset of symptoms.

Patients and Methods

This is a case-control observational study including patients admitted for their first AMI, either with ST-segment elevation (STEMI) or without ST elevation (NSTEMI), with an LVEF > 40% after a successful PCI. Echocardiography was repeated after 6 months, and the patients were divided into two groups, according to whether LV remodeling was determined on echocardiography.

Results

Of the 253 AMI patients (mean 66 aged ± 13 years), including 185 males (73%), 61 (24%) presented signs of LV remodeling. In univariate logistic regression analysis, age, male sex, smoking history, hypertension, hypercholesterolemia, Killip class, renal function, peak creatine phosphokinase - MB level, 2- and 3-vessel coronary artery disease (CAD), and several echocardiographic parameters were significantly associated with LV remodeling (P<0.05). In multivariate logistic regression analysis harmed (H) LS and SR, Killip class, 3-vessel CAD, and LV end-diastolic volume were outlined as independent predictors for LV remodeling. Receiver operating characteristic curve analyses showed that HLS and HLSR were the most powerful independent predictors for LV remodeling (P<0.001), with an area under the curve (AUC) of 0.85 (sensitivity 83%; specificity 84%; p <0.001) and 0.77 (sensitivity 93; specificity 61%; p <0.001), respectively. The identified cut-off values for predictor variables were HLS< -11%, and HLSR< -0.65s^-1.

Conclusion

We concluded that 2D-STE was the best method to evaluate LV remodeling in patients with AMI and midrange or preserved LVEF following myocardial revascularization by a PCI.

Comparison of Repeated Doses of C-kit-Positive Cardiac Cells versus a Single Equivalent Combined Dose in a Murine Model of Chronic Ischemic Cardiomyopathy

Using a murine model of chronic ischemic cardiomyopathy caused by an old myocardial infarction (MI), we have previously found that three doses of 1 × 10⁶ c-kit positive cardiac cells (CPCs) are more effective than a single dose of 1 × 10⁶ cells. The goal of this study was to determine whether the beneficial effects of three doses of CPCs (1 × 10⁶ cells each) can be fully replicated by a single combined dose of 3 × 10⁶ CPCs. Mice underwent a 60-min coronary occlusion; after 90 days of reperfusion, they received three echo-guided intraventricular infusions at 5-week intervals: (1) vehicle × 3; (2) one combined dose of CPCs (3 × 10⁶) and vehicle × 2; or (3) three doses of CPCs (1 × 10⁶ each). In the combined-dose group, left ventricular ejection fraction (LVEF) improved after the 1st CPC infusion, but not after the 2nd and 3rd (vehicle) infusions. In contrast, in the multiple-dose group, LVEF increased after each CPC infusion; at the final echo, LVEF averaged 35.2 ± 0.6% (p < 0.001 vs. the vehicle group, 27.3 ± 0.2%). At the end of the study, the total cumulative change in EF from pretreatment values was numerically greater in the multiple-dose group (6.6 ± 0.6%) than in the combined-dose group (4.8 ± 0.8%), although the difference was not statistically significant (p = 0.08). Hemodynamic studies showed that several parameters of LV function in the multiple-dose group were numerically greater than in the combined-dose group (p = 0.08 for the difference in LVEF). Compared with vehicle, cardiomyocyte cross-sectional area was reduced only in the multiple-dose group (-32.7%, 182.6 ± 15.1 µm² vs. 271.5 ± 27.2 µm², p < 0.05, in the risk region and -28.5%, 148.5 ± 12.1 µm² vs. 207.6 ± 20.5 µm², p < 0.05, in the noninfarcted region). LV weight/body weight ratio and LV weight/tibia length ratios were significantly reduced in both cell treated groups vs. the vehicle group, indicating the attenuation of LV hypertrophy; however, the lung weight/body weight ratio was significantly reduced only in the multiple-dose group, suggesting decreased pulmonary congestion. Taken together, these results indicate that in mice with chronic ischemic cardiomyopathy, the beneficial effects of three doses of CPCs on LV function and hypertrophy cannot be fully replicated with a single dose, notwithstanding the fact that the total number of cells delivered with one or three doses is the same. Thus, it is the multiplicity of doses, and not the total number of cells, that accounts for the superiority of the repeated-dose paradigm. This study supports the idea that the efficacy of cell therapy in heart failure can be augmented by repeated administrations.

The Role of Epoxyeicosatrienoic Acids in Cardiac Remodeling

Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid by cytochrome P450 (CYP) epoxygenases, which include four regioisomers: 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET. Each of them possesses beneficial effects against inflammation, fibrosis, and apoptosis, which could combat cardiovascular diseases. Numerous studies have demonstrated that elevation of EETs by overexpression of CYP2J2, inhibition of sEH, or treatment with EET analogs showed protective effects in various cardiovascular diseases, including hypertension, myocardial infarction, and heart failure. As is known to all, cardiac remodeling is the major pathogenesis of cardiovascular diseases. This review will begin with the introduction of EETs and their protective effects in cardiovascular diseases. In the following, the roles of EETs in cardiac remodeling, with a particular emphasis on myocardial hypertrophy, apoptosis, fibrosis, inflammation, and angiogenesis, will be summarized. Finally, it is suggested that upregulation of EETs is a potential therapeutic strategy for cardiovascular diseases. The EET-related drug development against cardiac remodeling is also discussed, including the overexpression of CYP2J2, inhibition of sEH, and the analogs of EET.

Comparison of the Efficacy and Safety of Sacubitril/Valsartan versus Ramipril in Patients With ST-Segment Elevation Myocardial Infarction

The role of sacubitril and/or valsartan in patient with heart failure (HF) is established. Whether sacubitril and/or valsartan plays a role in improving outcomes in patients after ST-segment elevation myocardial infarction (STEMI) is unknown. The current study aims to comparing the efficacy and safety of sacubitril and/or valsartan versus ramipril in post-STEMI patients. Patients presenting with STEMI were randomized to receive either sacubitril and/or valsartan or ramipril after primary percutaneous coronary intervention. The main efficacy endpoint was major adverse cardiac events (MACE) at 30 days and 6 months, defined as a composite of cardiac death, myocardial infarction, and HF hospitalizations. Multiple secondary clinical safety and efficacy endpoints were examined. A total of 200 patients were randomized from January 2018 to March 2019, mean age 54.5±10.4, 87% men, 75% presented with anterior wall STEMI. Baseline clinical and echocardiographic characteristics were comparable between groups. The primary endpoint of MACE was similar with sacubitril/valsartan versus ramipril at 30 days (p = 0.18); however, at 6 months, sacubitril/valsartan was associated with significant reduction of MACE (p = 0.005), mainly driven by reduction in HF hospitalizations (18% vs 36%, OR 0.40, 95% 0.22 to 0.75; p = 0.004). At 6 months, LV ejection fraction was higher with sacubitril/valsartan (46.8±12.5% vs 42.09±13.8%; p = 0.012), with improved LV remodelling (LV end diastolic dimension 50.6±3.9 mm vs 53.2±2.7 mm, p = 0.047; and LV end systolic dimension 36.1±3.4 mm versus 39.9±6.3 mm, p = 0.001) compared with ramipril. No difference in other efficacy or safety clinical endpoints was observed. In conclusion, early initiation of sacubitril/valsartan may offer clinical benefit and improvement in myocardial remodelling in post-STEMI patients.

Comparison of clinical outcomes and left ventricular remodeling after ST-elevation myocardial infarction between patients with and without diabetes mellitus

Left ventricular remodeling (LVR) after ST-elevation myocardial infarction (STEMI) is generally thought to be an adaptive but compromising phenomenon particularly in patients with diabetes mellitus (DM). However, whether the extent of LVR is associated with poor prognostic outcome with or without DM after STEMI in the modern era of reperfusion therapy has not been elucidated. This was a single-center retrospective observational study. Altogether, 243 patients who were diagnosed as having STEMI between January 2016 and March 2019, and examined with echocardiography at baseline (at the time of index admission) and mid-term (from 6 to 11 months after index admission) follow-up were included and divided into the DM (n = 98) and non-DM groups (n = 145). The primary outcome was major adverse cardiovascular events (MACEs) defined as the composite of all-cause death, heart failure (HF) hospitalization, and non-fatal myocardial infarction. The median follow-up duration was 621 days (interquartile range: 304–963 days). The DM group was significantly increased the rate of MACEs (P = 0.020) and HF hospitalization (P = 0.037) compared with the non-DM group, despite of less LVR. Multivariate Cox regression analyses revealed that the patients with DM after STEMI were significantly associated with MACEs (Hazard ratio [HR] 2.79, 95% confidence interval [CI] 1.20–6.47, P = 0.017) and HF hospitalization (HR 3.62, 95% CI 1.19–11.02, P = 0.023) after controlling known clinical risk factors. LVR were also significantly associated with MACEs (HR 2.44, 95% CI 1.03–5.78, P = 0.044) and HF hospitalization (HR 3.76, 95% CI 1.15–12.32, P = 0.029). The patients with both DM and LVR had worse clinical outcomes including MACEs and HF hospitalization, suggesting that it is particularly critical to minimize LVR after STEMI in patients with DM.

Genetic ablation of fibroblast activation protein alpha attenuates left ventricular dilation after myocardial infarction

Introduction

Regulating excessive activation of fibroblasts may be a promising target to optimize extracellular matrix deposition and myocardial stiffness. Fibroblast activation protein alpha (FAP) is upregulated in activated fibroblasts after myocardial infarction (MI), and alters fibroblast migration in vitro. We hypothesized that FAP depletion may have a protective effect on left ventricular (LV) remodeling after MI.

Materials and methods

We used the model of chronic MI in homozygous FAP deficient mice (FAP-KO, n = 51) and wild type mice (WT, n = 55) to analyze wound healing by monocyte and myofibroblast infiltration. Heart function and remodeling was studied by echocardiography, morphometric analyses including capillary density and myocyte size, collagen content and in vivo cell-proliferation. In non-operated healthy mice up to 6 months of age, morphometric analyses and collagen content was assessed (WT n = 10, FAP-KO n = 19).

Results

Healthy FAP-deficient mice did not show changes in LV structure or differences in collagen content or cardiac morphology. Infarct size, survival and cardiac function were not different between FAP-KO and wildtype mice. FAP-KO animals showed less LV-dilation and a thicker scar, accompanied by a trend towards lower collagen content. Wound healing, assessed by infiltration with inflammatory cells and myofibroblasts were not different between groups.

Conclusion

We show that genetic ablation of FAP does not impair cardiac wound healing, and attenuates LV dilation after MI in mice. FAP seems dispensable for normal cardiac function and homeostasis.

Effect of Guanxin V in animal model of acute myocardial infarction

Background

Acute myocardial infarction (AMI) is the most serious and lethal manifestation of coronary heart disease worldwide, presenting extremely high disability and mortality. Our previous studies have shown that Guanxin V (GXV) could significantly improve the cardiac function and the blood flow dynamics, and reduce serum levels of inflammatory factors in AMI rats, thus triggering ventricular remodeling (VR) at post-AMI.

Methods

An in vivo AMI model was established in Syrian hamsters by performing the ligation of the left anterior descending coronary artery. Syrian hamsters were randomly divided into four groups, namely Sham operation group (n = 12), AMI group (n = 12), GXV group (GXV 6 g/Kg/d, n = 12), and Tranilast group (Tra 105 mg/Kg/d, n = 12). Drug intervention was conducted for consecutive 8 weeks. Relative biological indicators were measured in the 4th and 8th week, respectively.

Results

Cardiac functions were improved, and the infarcted size and heart weight index were limited in Syrian hamsters of GXV and Tra groups compared with those in AMI group. Furthermore, GXV was able to decrease the number of mast cells and chymase level in Syrian hamsters with AMI. Administration of GXV remarkably inactivated the renin-angiotension-aldosterone system, and alleviated myocardial fibrosis and cardiomyocyte apoptosis, thus slowing down VR at post-AMI.

Conclusion

GXV slows down the process of VR at post-AMI by reducing chymase level and mast cells number, as well as inactivating the reninangiotension-aldosterone system..

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03211-7.

Door-to-unload: left ventricular unloading before reperfusion in ST-elevation myocardial infarction

ST-elevation myocardial infarction treatment in the modern era has focused on minimizing time of ischemia by reducing door-to-balloon time to limit infarct size and improve survival. Although there have been significant improvements in minimizing time to coronary reperfusion, the incidence of heart failure following a myocardial infarction has remained high. Preclinical studies have shown that unloading the left ventricle for 30 min prior to coronary reperfusion can reduce infarct size and promote myocardial recovery. The DTU-STEMI randomized prospective trial will test the hypothesis that left ventricular unloading for at least 30 min prior to coronary reperfusion will improve infarct size and heart failure-related events as compared with the current standard of care.

Beneficial Roles of Cellulose Patch-Mediated Cell Therapy in Myocardial Infarction: A Preclinical Study

Biological scaffolds have become an attractive approach for repairing the infarcted myocardium and have been shown to facilitate constructive remodeling in injured tissues. This study aimed to investigate the possible utilization of bacterial cellulose (BC) membrane patches containing cocultured cells to limit myocardial postinfarction pathology. Myocardial infarction (MI) was induced by ligating the left anterior descending coronary artery in 45 Wistar rats, and patches with or without cells were attached to the hearts. After one week, the animals underwent echocardiography to assess for ejection fraction and left ventricular end-diastolic and end-systolic volumes. Following patch formation, the cocultured cells retained viability of >90% over 14 days in culture. The patch was applied to the myocardial surface of the infarcted area after staying 14 days in culture. Interestingly, the BC membrane without cellular treatment showed higher preservation of cardiac dimensions; however, we did not observe improvement in the left ventricular ejection fraction of this group compared to coculture-treated membranes. Our results demonstrated an important role for BC in supporting cells known to produce cardioprotective soluble factors and may thus provide effective future therapeutic outcomes for patients suffering from ischemic heart disease.

Application of Cell, Tissue, and Biomaterial Delivery in Cardiac Regenerative Therapy

Cardiovascular diseases (CVD) are the leading cause of death around the world, being responsible for 31.8% of all deaths in 2017 (Roth, G. A. et al. The Lancet 2018, 392, 1736-1788). The leading cause of CVD is ischemic heart disease (IHD), which caused 8.1 million deaths in 2013 (Benjamin, E. J. et al. Circulation 2017, 135, e146-e603). IHD occurs when coronary arteries in the heart are narrowed or blocked, preventing the flow of oxygen and blood into the cardiac muscle, which could provoke acute myocardial infarction (AMI) and ultimately lead to heart failure and death. Cardiac regenerative therapy aims to repair and refunctionalize damaged heart tissue through the application of (1) intramyocardial cell delivery, (2) epicardial cardiac patch, and (3) acellular biomaterials. In this review, we aim to examine these current approaches and challenges in the cardiac regenerative therapy field.

Extracellular vesicles from anoxia preconditioned mesenchymal stem cells alleviate myocardial ischemia/reperfusion injury

Extracellular vesicles (EVs) produced by anoxia-preconditioned mesenchymal stem cells (MSCs) may afford greater cardioprotection against myocardial ischemia-reperfusion injury (MIRI) than EVs derived from normoxic MSCs. Here, we isolated EVs from mouse adipose-derived MSCs (ADSCs) subjected to anoxia preconditioning or normoxia and evaluated their ability to promote survival of mouse cardiomyocytes following MIRI in vivo and anoxia/reoxygenation (AR) in vitro. Injection of anoxia-preconditioned ADSC EVs (Int-EVs) reduced both infarct size and cardiomyocyte apoptosis to a greater extent than normoxic ADSC EVs (NC-EVs) in mice subjected to MIRI. Sequencing EV-associated miRNAs revealed differential upregulation of ten miRNAs predicted to bind thioredoxin-interacting protein (TXNIP), an inflammasome- and pyroptosis-related protein. We confirmed direct binding of miRNA224-5p, the most upregulated miRNA in Int-EVs, to TXNIP and asserted through western blotting and apoptosis assays a critical protective role for this miRNA against AR-induced cardiomyocyte death. Our results suggest that ischemia-reperfusion triggers TXNIP-induced inflammasome activation in cardiomyocytes, which leads to apoptosis rather than pyroptosis due to low basal levels of the pyroptosis executioner protein gasdermin D in these cells. The antiapoptotic effect of EV-associated miRNA224-5p would in turn result from TXNIP downregulation, which prevents caspase-1-mediated degradation of GATA4 and sustains the expression of Bcl-2.

Identifying Myocardial Infarction Using Hierarchical Template Matching-Based Myocardial Strain: Algorithm Development and Usability Study

Background

Myocardial infarction (MI; location and extent of infarction) can be determined by late enhancement cardiac magnetic resonance (CMR) imaging, which requires the injection of a potentially harmful gadolinium-based contrast agent (GBCA). Alternatively, emerging research in the area of myocardial strain has shown potential to identify MI using strain values.

Objective

This study aims to identify the location of MI by developing an applied algorithmic method of circumferential strain (CS) values, which are derived through a novel hierarchical template matching (HTM) method.

Methods

HTM-based CS H-spread from end-diastole to end-systole was used to develop an applied method. Grid-tagging magnetic resonance imaging was used to calculate strain values in the left ventricular (LV) myocardium, followed by the 16-segment American Heart Association model. The data set was used with k-fold cross-validation to estimate the percentage reduction of H-spread among infarcted and noninfarcted LV segments. A total of 43 participants (38 MI and 5 healthy) who underwent CMR imaging were retrospectively selected. Infarcted segments detected by using this method were validated by comparison with late enhancement CMR, and the diagnostic performance of the applied algorithmic method was evaluated with a receiver operating characteristic curve test.

Results

The H-spread of the CS was reduced in infarcted segments compared with noninfarcted segments of the LV. The reductions were 30% in basal segments, 30% in midventricular segments, and 20% in apical LV segments. The diagnostic accuracy of detection, using the reported method, was represented by area under the curve values, which were 0.85, 0.82, and 0.87 for basal, midventricular, and apical slices, respectively, demonstrating good agreement with the late-gadolinium enhancement–based detections.

Conclusions

The proposed applied algorithmic method has the potential to accurately identify the location of infarcted LV segments without the administration of late-gadolinium enhancement. Such an approach adds the potential to safely identify MI, potentially reduce patient scanning time, and extend the utility of CMR in patients who are contraindicated for the use of GBCA.